A student mixes 20.0gof white KCl crystals with distilled water in a beaker. After the mixture was stirred, no crystals are visible and the solution is clear. After several days, all of the water evaporates and white crystals are found in the beaker. Which of following pieces of experimental evidence would best help the student to confirm that a new compound had not been made and that only a physical change occurred?
a- The solution does not change color after stirring.
b- The KCl crystals are no longer visible after mixing with water.
c- There is a temperature change in the solution during the dissolving process.
d- After the water has evaporated, the white crystals in the beaker have a mass of 20.0g

Answers

Answer 1

Answer:d

Explanation: over time water evaporates which leaves you with the white crystals mass

Answer 2

A student in a beaker mixes 20.0 g of white KCl crystals with distilled water; no crystals are visible, and the solution is clear, indicating that the physical change has occurred, which is that after the water has evaporated, the white crystals in the beaker have a mass of 20.0 g; that is option d.

What is the significance of the physical change?

The physical change includes the change in the shape and size of the substances but not the chemical change, as in the case of here the crystal, which is left behind after the evaporation of the solution without any change in the chemical composition.

Hence, a student in a beaker mixes 20.0 g of white KCl crystals with distilled water; no crystals are visible, and the solution is clear, indicating that the physical change has occurred, which is that after the water has evaporated, the white crystals in the beaker have a mass of 20.0 g; that is option d.

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Related Questions

distinguizh between the 4 states ofmatter

Answers

Answer:

There are four natural states of matter: Solids, liquids, gases and plasma. ... Solids have a definite shape, as well as mass and volume, and do not conform to the shape of the container in which they are placed. Solids also have a high density, meaning that the particles are tightly packed together.

Explanation:

hope this helps! goodluck & enjoy the rest of ur day or night.

which of the following is a characteristic of the modern periodic table

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They are all radioactive

magine that you are a water molecule in a group of many water molecules. Write a letter to a friend telling them about your journey through the water cycle on Earth. You can begin your journey anywhere you’d like, but you must complete an entire cycle and end the journey where you began. Write your letter in complete sentences. Use each of the following terms correctly in your letter: • condensation • evaporation • precipitation • collection (HELP PLS ILL GIVE 54 points *all my points* AND GIVE BRAINLIEST HELP PLS)

Answers

Answer:

Explanation:

One day I was sitting on a leaf, in the early morning if a Tuesday, and I was just relaxing there. I then heard Bob( the water molecule next to me) say that he heard it was going to get pretty hot today. As the day went on I started to get pretty warm and I starting to evaporate and fly into the sky! It was really weird to see the world from up high. I stayed up there bouncing between clouds with Bob for a few hours, until the wind started to pick up and it got colder. I then started to shiver and began condensing with the other water molecules (and Bob). As it got colder we began to plummet to the earth really fast in the precipitate form of a water droplet. We hit the ground with a big ker-plop! I looked around me and we weren't the only ones. A bunch of other droplets had started to collect and form a puddle.

Hope this helps!

When 0.019 mol of aluminum sulfate are dissolved in enough water to make 905 milliliters of solution, what is the molar concentration of aluminum ions? Answer in units of M

Answers

Moles sulfate ions in Al2(SO4)3
Molarity= molessulfateions/liters of solution
= 3*.042/.763 moles/liter 12.4

In order for a chemical reaction to take place, a certain amount of _____ must be present.

Answers

Answer:

The answer is energy. Please give me Brainliest!

Explanation:

Raising the concentrations of reactants makes the reaction happen at a faster rate. For a chemical reaction to occur, there must be a certain number of molecules with energies equal to or greater than the activation energy.

A tank of syngas produced by coal gasification contains 60.0% carbon monoxide, 30.0% hydrogen, and 10.0% carbon dioxide. What is the mass of hydrogen (in g) in 1.00 cubic meter of this syngas mixture at 1.00 atm and 25.0 °C? (1 m³ = 1000 L)

Answers

Considering the ideal gas law, the mass of hydrogen is 24.552 grams.

An ideal gas is a theoretical gas that is considered to be composed of randomly moving point particles that do not interact with each other. Gases in general are ideal when they are at high temperatures and low pressures.

An ideal gas is characterized by three state variables: absolute pressure (P), volume (V), and absolute temperature (T). The relationship between them constitutes the ideal gas law, an equation that relates the three variables if the amount of substance, number of moles n, remains constant and where R is the molar constant of the gases:

P× V = n× R× T

In this case, you know:

P= 1 atmV= 1 m³= 1000 Ln= ?R= 0.082[tex]\frac{atmL}{molK}[/tex]T= 25 °C= 298 °K

Replacing in the ideal gas law:

1 atm× 1000 L = n× 0.082[tex]\frac{atmL}{molK}[/tex]× 298 K

Solving:

[tex]n=\frac{1 atmx1000 L}{0.082 \frac{atmL}{molK}x298 K}[/tex]

n= 40.92 mol

The mol of syngas mixture is 40.92 mol.

Syngas mixture contains 30.0% hydrogen. So, there is a mol fraction of [tex]x_{hydrogen} =[/tex]0.3 . Thus, the mols of hydrogen in syngas mixture is calculated as:

40.92 moles of syngas mixture× 0.3= 12.276 moles of hydrogen

Finally, being the molar mass of hydrogen H₂ 2 [tex]\frac{g}{mole}[/tex], then the mass is:

[tex]12.276 molesx\frac{2 grams}{1 mole}[/tex]= 24.552 grams

In summary, the mass of hydrogen is 24.552 grams.

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pls help me out!! perform the mathematical operation and report to the appropriate number of significant figures 0.00325136-1.76527

Answers

Answer:

-1.76202

Explanation: Because the operation is subtraction, you would count the number of digits after the decimal point. Then you would perform the operation and round your answer to the SMALLER number of digits after the decimal point.

Which of the following could be classified as producing a physical change?
A. Burning a candle
B. Leaving a bicycle outside to rust
C. Bending sheet metal
D. Toasting a slice of bread

Answers

D which is Toasting a slice of bread

Answer:

C.  Bending sheet metal.

Explanation:

The metal is still intact.  No change in chemical bonds have occurred.

Burning a candle is converting wax into heat, CO2 and carbon soot.

A rusting bicycle is converting goof iron, Fe, into iron oxide (rust, Fe2O3)

Toasting bread is more difficult to define.  If the bread is just warmed, then it is physical.  If it is toasted (browned/burned), then a few surface molecules have been converted into tasty carcinogens, my favorite poison.

How do you think dry cleaning works?

Answers

During dry cleaning, the pump pulls solvent from the tank and sends it through the filters to remove any impurities. The filtered solvent then enters the cylinder, where it interacts with the fabrics and removes any soil. The solvent then travels back into the holding tank so it can begin the process again.

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can someone in here please answer there question for the love of god

Answers

I can’t see the problem

Calculate the molar mass of NH4NO3. Molar mass of NH4NO3 = g/mol.

Answers

The molar mass of NH4NO3 in g/mol is 80g/mol.

HOW TO CALCULATE MOLAR MASS:

The molar mass of a compound can be calculated by summing the atomic masses of its constituent elements.

In ammonium nitrate (NH4NO3), there are nitrogen, hydrogen, and oxygen elements.

Atomic mass of nitrogen = 14Atomic mass of oxygen = 16Atomic mass of hydrogen = 1

Molar mass of NH4NO3 = 14 + 1(4) + 14 + 16(3)

Molar mass of NH4NO3 = 80g/mol

Therefore, the molar mass of NH4NO3 in g/mol is 80g/mol.

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Answer:

80g/mol

Explanation:

edge 2022

The electron-domain geometry of a sulfur-centered compound is trigonal bipyramidal. The hybridization of the central sulfur atom is ________.

Answers

The hybridization state of the central sulfur atom is sp3d.

The valence shell electron pair repulsion theory describes the shape of molecules in terms of the number of electron pairs that surround the valence shell of the central atom in the molecule.

There are certain molecular shapes that are associated with certain hybridization states of the central atom. Since the central sulfur atom is trigonal bipyramidal, the hybridization state is sp3d.

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What is one way humans can control landfills?
(25 Points)
They can throw away less garbage.
They can throw away more garbage.
They can pollute the land.
None of the above.

Answers

none of the above is the answer i think?!

Answer:

none of the above

Explanation:

if we threw away less garbage it would just end up polluting somewhere else

if we threw away more garbage it would just add to the landfills

and if we pollute the land any more than we already have there's no point in even trying

therefore the most logical answer would b none of the above

What can form along faults when pushed together or pulled apart?
O Mountains
O Volcanoes
O Both

Answers

Answer:

Both

Explanation:

if you pull a mountain a part that would be great consequences and if a volcano breaks there will be fire .

A Mountain is formed when two faults push together and a volcano is formed when two faults are pushed together and there is a pocket of air

What is the atomic mass, in amu, of this atom?

Answers

Answer:precisely 1/12 the mass of an atom of carbon-12.

Explanation:The carbon-12 (C-12) atom has six protons and six neutrons in its nucleus. In imprecise terms, one AMU is the average of the proton rest mass and the neutron rest mass.

Who turned the ragged Continental Army into a more efficient fighting force?

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Von Steuben turned the ragged Continental Army into a more effective fighting force by drilling and teaching the army discipline

Sodium has a density of 1.95 g/mL If the volume of some sodium is 9.0 L what is the mass

Answers

Answer:

17550g

Explanation:

You want to use the equation D=M/V. You are given density in g/mL, so you just need to multiply that by 9L, but first you want the mL and L to match, so you change the 9L to 9000mL (knowing there is 1000mL in 1L). Then solve algebraically by multiplying the 9000mL and the 1.95g/ml, making the mL cancel, leaving you with your answer in grams.

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50 POINTS!!!! PLEASE HELP I AM BEGGING!!!!!!
3CH4 and C3H12 have the same number and kind of elements. How are they different?

Answers

3CH4 refers to three molecules of a
compound and C3H12 refers to only one
molecule of a compound.
3CH4 and C3H12 are actually different
molecules though they contain the same
number and types of atoms. Recall that both
of them are hydrocarbons hence they
contain only hydrogen and carbon.
3CH4 refers to three molecules of methane
while C3H12 refers to one molecule of
diphenyl methane. Hence 3CH4 refers to
three molecules of a compound and C3H12
refers to only one molecule of a compound.

Which neutral atom is isoelectronic with N-3?

Answers

The neutral atom is isoelectronic with N⁻³ is Neon (Ne).

Isoelectronic are those which have same number of electrons or we can say that same electronic structure.

For finding out that the species are isoelectronic , we just have to count there no. of electrons of atoms and if they have same no. of electron then they said to be isoelectronic species.

no. of electrons in Nitrogen N = 7 ( atomic no.)

no. of electrons in Nitride ion N⁻³ = 7 + 3 = 10

no. of electrons in Neon Ne = 10 ( atomic no. and neutral atom)

so, no. of electrons in Nitride ion N⁻³  = no. of electron in Neon Ne

this means , N⁻³ , Nitride ion is isoelectronic with Neon Ne.

Thus, The neutral atom is isoelectronic with N⁻³ is Neon (Ne).

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Describe in short about the paper chromatography. ​

Answers

Answer:

Paper chromatography is a method used to distinguish or separate coloured substance mixtures.

In the image, take an example of colured chemical placed in a glass beaker. If a paper is placed in that chemical, coloured spots are separated and displayed on the chromatogram.

It was founded in 1944 A.D by a scientist called Erwin Cargaff.

Gaseous chlorine, Cl2, was combined with 0.532g of Titanium, and 2.108 g of TixCly were collected. What is the empirical formula of titanium chloride?

Answers

Answer:

TiCl₄

Explanation:

From the law of conservation of mass, the mass of the reactants must equal the mass of the products. In other words:

[tex]\displaystyle \text{m Cl$_2$} + \text{ m Ti} = \text{ m Ti$_x$Cl$_y$}[/tex]

Find the mass of chlorine gas reacted:

[tex]\displaystyle \begin{aligned} \text{ m Cl$_2$} + (0.532 \text{ g}) & = (2.108 \text{ g)} \\ \\ \text{m Cl$_2$} & = 1.576 \text{ g} \end{aligned}[/tex]

Find the number of moles of each reactant using their respective molecular weights:

[tex]\displaystyle 1.576 \text{ g Cl$_2$} \cdot \frac{1 \text{ mol Cl$_2$}}{70.90\text{ g Cl$_2$}} \cdot \frac{2\text{ mol Cl}}{1\text{ mol Cl$_2$}} = 0.04446\text{ mol Cl}[/tex]

And:

[tex]\displaystyle 0.532\text{ Ti} \cdot \frac{1\text{ mol Ti}}{47.87\text{ g Ti}} = 0.0111\text{ mol Ti}[/tex]

To find the empirical formula, all values by the smallest value:

[tex]\displaystyle \begin{aligned} \frac{0.0111\text{ mol Ti}}{0.0111} & = \frac{0.04446\text{ mol Cl}}{0.0111} \\ \\ 1\text{ mol Ti} & \approx 4\text{ mol Cl}\end{aligned}[/tex]

Hence, there are four moles of chlorine for every one mole of titanium.

In conclusion, our empirical formula is TiCl₄.

What does it mean to optimize a solution ?
How are solutions optimize

Answers

Question

What does it mean to optimize a solution?

To find out best possible solution for a given problem within the given constraint is generally termed as optimization

How are solution optimize ?

To solve an optimization problem, begin by drawing a picture and introducing variables. Find an equation relating the variables. Find a function of one variable to describe the quantity that is to be minimized or maximized. Look for critical points to locate local extrema.

How can you find each of the 4 blood vessels when dissecting?

Answers

Answer:

that's a weird question

Explanation:

why do you need to know that?

What effect do shiny metals have on radiant energy?

Answers

Answer: Metals conduct heat and reduce the kinetic energy within the components that need to remain cool.

Explanation:

SEP Construct Explainations: Explain how a substance's flammability can indicate a chemical change.​

Answers

Answer:Wood for barbucue.

Explanation:

Reactions cannot occur without a certain minimum amount of energy. What is this minimum amount of energy called?
the activation energy
the activated complex
the kinetic energy of reactants
the potential energy of products

Answers

Hello!!
It should be
“the activation energy”

How does VSEPR theory describe the double bonds between the central carbon atom and each oxygen atom of Co2?

Answers

The double bonds in CO2 are counted as single regions of electron density.

The valence shell electron pair repulsion theory VSEPR  is a description of the shape of molecules based on the number of electron pairs that surround the central atom in the molecule. Double bonds are counted as a single region of electron density.

Hence, the two double bonds in CO2 are counted as two regions of electron density around the central carbon atom. Hence, the molecule is liner at a bond angle of 180 degrees.

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Solve pls brainliest
The two green substances are not same thing because some of their properties are different and some of them are the same. If they were the same substance, all of their properties would have to be the same.


How could the explanation be improved?

Answers

Answer:

Even though the two substances possess many similarities, they have some unique properties. In turn, since they have the same properties, if they were the same substance, it would make matters worse, if the same chemical was in two different places, there would not be a difference between them since they are the same, just as it is with are two different chemicals would have differing properties since they are two properties would vary from one another since they are 2 totally different things!

4. When a turbine spins, it generates electrical energy and that is where it gets its name from.

Answers

if it’s hydraulic turbine then it’s potential and kinetic energy and if it’s a thermal process then heat energy from the fuel burnt runs the turbine

What does the answer of element 3Na2S2O3?

Answers

Answer:

Explanation:

3× 22+2×32+ 6×16=

66+64+96=236

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